The present invention relates to a throttle opening degree control apparatus for an internal combustion engine, and more particularly to a throttle opening degree control apparatus for an internal combustion engine that has, for example, an electronically controlled throttle valve that is controlled with an actuator.
For example, Japanese Laid-Open Patent Publication No. 9-310637 discloses a typical throttle opening degree control apparatus for an internal combustion engine. When the depression degree of an acceleration pedal is equal to or less than a predetermined value, the apparatus of the publication determines an actuation speed based on computation results of target opening degree computation means for throttle opening degree, and drives an actuator such that the throttle valve is moved at the determined actuation speed. When the depression degree of the acceleration pedal surpasses the predetermined value, the control apparatus drives the actuator at a speed that is less than a predetermined upper limit speed, so that a shock due to acceleration is reduced. Therefore, until the throttle opening degree reaches a predetermined degree, the vehicle is smoothly accelerated according to the demand of the driver. After the throttle opening degree reaches the predetermined degree, the throttle valve is moved at a slower speed so that acceleration shock is reduced.
While a vehicle is running, the direction of torque transmitted between a vehicle driving system and an internal combustion engine is occasionally reversed. Such a reverse creates a torque shock in a transmission, which is a part of the vehicle driving system. The greater the difference between the speed of the engine and the speed of the vehicle driving system at the time of a reverse, the greater the torque shock caused by the reverse becomes. This degrades the drivability.